$ git clone -n https://src.fedoraproject.org/rpms/libpng12.git /var/lib/mock/f45-build-16798-491/root/chroot_tmpdir/scmroot/libpng12
Cloning into '/var/lib/mock/f45-build-16798-491/root/chroot_tmpdir/scmroot/libpng12'...
$ git fetch origin 1d3226fbdbb3e1b017a3156c793c25b0cc02140d:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/libpng12
 * [new ref]         1d3226fbdbb3e1b017a3156c793c25b0cc02140d -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 1d3226f Rebuilt for https://fedoraproject.org/wiki/Fedora_45_Mass_Rebuild